Project Summary/Abstract As of mid-May, 2020, severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19 disease, has been diagnosed in more than 1.3 million persons in the United States and accounted for more than 80,000 US deaths. Identifying persons infected with SARS-CoV-2 before they present to health care can reduce transmission and flatten the epidemic curve. The San Francisco Bay Area was particularly hard hit early in the COVID-19 pandemic in the United States, and like many parts of the United States, has substantial racial/ethnic disparities in the distribution of cases of COVID-19 in the City. The eastern parts of the City have the highest case rates, with most heavily impacted communities including the Mission, Bayview and Sunnydale neighborhoods, and the Tenderloin, but relatively few COVID-19 testing sites exist there. In addition, outbreaks have been occurring in congregate living situations in San Francisco, where testing can be difficult to perform. We plan to increase SARS-CoV-2 testing through 2 low-barrier testing approaches to identify previously undiagnosed persons. First, we will use a mobile testing unit to reach persons in facilities and neighborhoods where COVID-19 rates are high. Second, we will conduct testing through a community mobilization event in a heavily impacted neighborhood in the southeast San Francisco, testing more than 3000 persons over a four-day time period. We will integrate HIV testing into SARS-CoV-2 testing, as rates of HIV testing have dramatically declined since the beginning of the COVID-19 pandemic, and there is substantial overlap in the populations at risk of both types of infection. These activities will have the additional benefit of increasing capacity at the 2 Clinical Research Sites of the San Francisco Bay Clinical Trials Unit to conduct COVID-19 research, including trials of vaccines and therapeutic interventions.